Answer:
If you are 100% the pack leader so your dog is secure when you leave him and you take him for a long walk that tires him out before you leave and another long walk when you get back, your chances are good that your dog will be fine. In nature dogs get up in the morning and walk to find food.
So you if you simulate that by pack-walking your dog for a long time before you leave to tire him out and then feed him he will go into rest mode and should be OK until you return. It is important that you pack-walk him and not allow him to walk you. If you concentrate on exercise and leadership matching the needs of the dog, the dog should be fine. The higher energy the dog, the longer walk or even jog/run/bike ride the dog will need to go on.
Placing a backpack on a higher energy dog helps to tire him out and give him a sense of a job to accomplish. A tired dog is a good dog. Dogs with pent up energy and that do not know their place in their pack generally are the dogs that act out. It is important that the dog heels on the lead so he sees you as his leader.
If your dog is restless when you leave and causes a commotion it means he has energy to burn and/or he is not secure with you being away from him. See Separation Anxiety in Dogs for more info.
If your dog is restless when you leave and causes a commotion it means he has energy to burn and/or he is not secure with you being away from him. See Separation Anxiety in Dogs for more info.